Related Articles

U.S. Department of Agriculture plant hardiness zones measure average winter low temperatures, important to know for growing plants that yield flowers, fruits and seeds, but not for grasses. Grasses spread by underground runners called rhizomes or above ground runners called stolons and are divided into cool season and warm season types. The U.S. National Arboretum has mapped zones to help you match grass seed to appropriate climate.

Cool Humid Zone

Cool season grasses thrive in temperatures of 65 to 75 degrees Fahrenheit. They tend to be green in winter and brown in summer. New England, the states surrounding the Great Lakes, the Pacific Northwest and the Northern California coast are in the cool humid zone. Blue grass (Poa spp.), bentgrass (Agrostis spp), fescues (Festuca spp) and ryegrass (Lilium spp.) are suited to the this zone.Although buffalograss (Stenotaphrum secundatum) and zoysiagrass (Zoysia japonica) are both warm season grasses they are sometimes grown in the southern and western parts of the cool humid zone.

Cool Arid Zone

The Dakotas, Nebraska and Missouri west to eastern Washington, eastern Oregon and the Sierra Nevada mountains in California are in the cool arid zone. If you have irrigation you can grow any cool season grass in this zone. Canada bluegrass (Poa compressa) or wheatgrass (Triticum aestiyum) are sometimes planted in cooler parts that lack irrigation.

Warm Humid Zone

Warm season grasses like temperatures between 85 and 90 F. They tend to be green in summer and turn brown in winter. The warm humid zone includes the southeast west to most of Oklahoma and parts of east Texas. If you have irrigation, you can grow any warm season grass in this zone. Bermudagrass (Cynodon dactylon) is the most widely planted grass in this zone. Zoysiagrass is planted in the northern parts. Bahiagrass (Paspalum notatum) carpetgrass (Axonopus spp.) and St. Augustinegrass (Stenotaphrum secundatum) are commonly grown around the Gulf Coast.

Warm Arid Zone

The warm arid zone covers most of Texas, the southern parts of New Mexico and Arizona, plus California west of the Sierra Nevada mountains and north to the San Francisco Bay. You can grow any warm season grass in this zone if you can irrigate it. Bermudagrass, the most commonly planted arid zone grass, spreads both by rhizomes and stolons and is invasive in some areas. To control it you have to pull it up or smother it by black plastic; if you live in an area where irrigation is required you can deprive it of water. Buffalograss is increasingly grown in this zone.